I have a raspberry connected to an OpenWrt IPv4/IPv6 router. As you can see below, on the eth1 interface I get two ULA addresses: fd00::1f0/128 and fd00::27d5:6387:c8e5:3b1a/64
On the router, the fd00::/64 ULA prefix is set, for testing purposes. My questions are:
- Why are there two different ULA addresses?
- How are they created? Is the prefix advertised somehow from the router? Is it requested by the hosts on the network?
- What does the /128 mean on the first ULA addr? It does not make much sense to have a 128bit prefix length..
Running ip -a on my raspberry
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:e0:99:00:06:d3 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.10/24 brd 192.168.1.255 scope global dynamic noprefixroute eth1
valid_lft 41726sec preferred_lft 36326sec
inet6 fd00::1f0/128 scope global dynamic noprefixroute
valid_lft 42612sec preferred_lft 42612sec
inet6 fd00::27d5:6387:c8e5:3b1a/64 scope global mngtmpaddr noprefixroute
valid_lft forever preferred_lft forever
inet6 fe80::6e28:de2e:f0e0:ce5f/64 scope link
valid_lft forever preferred_lft forever